In an internal combustion engine, ambient intake air passes through a particulate filter and into the intakes of the various engine cylinders, whereupon the clean air mixes with a calibrated amount of fuel. The fuel/air mix is then ignited via spark or compression. The force of the fuel combustion occurring within the cylinders generates engine torque, which is then transmitted to an input member of a transmission. A coupled output member of the transmission thereafter delivers output torque to the drive axles to propel the vehicle.
Because of the importance of air flow to the combustion process, engine control units and various onboard processes require knowledge of the amount of air flow entering the cylinders. For this reason, a mass air flow (MAF) sensor is typically positioned near the air intakes of the engine. A typical MAF sensor outputs a frequency or period signal to the engine control unit. Conventional approaches to determining the mass air flow from such frequency information include directly sampling the frequency signal using, e.g., crank angle-based or time-based sampling. Crank angle-based sampling involves converting frequency value at a specific crank angle to a corresponding MAF value. Time-based sampling occurs on the frequency signal at calibrated intervals as opposed to at specific crank angles.